My Pyracantha has been attacked last year and is continueing to be seriously affected by a tiny caterpiller type creature that is found on the leaf, usualy just one per leaf. It seems to be in the leaf and causes the top fine skin of the leaf to lift or separate from the leaf like a flat blister. If I peel back the blister I will fine one of these creatures, just a few millimeters long, brown or black head and very thin, less than a millimeter thick. The whole shrub is affected and looks at first sight as if it has been splashed with water used to wash out a concrete mixer, some leaves are almost all white on one side only and some only partially white, when you peel off the dead skin of the blister, the leaf inside shows very little damage. What is this and how can I prevent the infestation.

14 Feb, 2010

Answers

Pyracantha leaf miner is difficult to control unless you use a systemic insecticide. Most have been taken off the market though the hand spray version of provado should do it. Don't spray when there are flowers on the plant though as bees are particularly susceptible to the poison and can take it back to their nest causing the whole nest to fail.

Spay once as the new leaves open but several week before the flower buds open and then once again after all the petals have dropped off the flowers.